Rory Stewart: We are very clear that we do not tie aid spending. There may be situations in which it is beneficial. For example, we have just put £70 million into British universities to find a universal cure for snake bites. That is a very good example of how we can solve a global public health problem through investment in British universities, but that is not tied aid; it is because British research and development, particularly the Liverpool School of Tropical Medicine, is the leader in this area. We can do this in many areas without feeling ashamed of ourselves, benefiting Britain and the world, and without tying our aid.